A carpenter bee is a type of bee belonging to the genus Xylocopa. These fascinating creatures are known for their remarkable woodworking abilities. Unlike honeybees and bumblebees that nest in hives or underground, carpenter bees construct their nests by tunneling into wood. They prefer dead or decaying wood, such as old tree trunks or untreated wooden structures.
Now, you might wonder why we should appreciate carpenter bees in our gardens. Well, they are exceptional pollinators!
These bees play a crucial role in the ecosystem by visiting a wide variety of flowering plants. As they move from flower to flower in search of nectar and pollen, they transfer pollen grains, enabling the plants to produce fruits and seeds. By supporting the pollination process, carpenter bees contribute to the overall health and productivity of our gardens.
You might have concerns about the potential damage carpenter bees can cause to wooden structures. However, it’s important to note that they typically target untreated or weathered wood. In a sustainable and organic garden, we can take steps to prevent or minimize damage while still appreciating these remarkable creatures.
By providing alternative nesting options, such as bee blocks or bee hotels made from untreated hardwood logs or blocks of wood, we can divert carpenter bees away from our wooden structures and provide them with suitable habitats.
It’s also worth mentioning that carpenter bees are generally harmless and rarely sting. The males, who often hover around their nesting sites, are territorial but lack a stinger. The females do possess stingers, but they are docile and only sting when provoked or threatened. So, there is no need to fear them while working in your garden.
By understanding and respecting the role of carpenter bees in the ecosystem, we can foster a harmonious relationship with these industrious pollinators.
Through sustainable gardening practices that prioritize plant diversity, organic pest control, and providing alternative nesting options, we can create a garden that thrives with the presence of carpenter bees while preserving the integrity of our wooden structures.
What is a Carpenter Bee?
The term carpenter bees apply to several different bees in the US that excavate tunnels in sound wood. Carpenter bees have a similar appearance to bumble bees, but the top surface of the abdomen is black, shiny, and almost entirely hairless. Females have a black face, while males’ face is white.
These bees get their common name due to the female carpenter bees’ habit of excavating nest site galleries in wood for their young. Carpenter bees are important pollinators that feed on nectar and pollen; they do not eat wood.
Bigger carpenter bees belong to the Xylocapa genus. Two native species, Xylocopa micans, and Xylocopa virginica, occur in the eastern US. Several native carpenter bees also happen in the western US.
Carpenter bees can often be seen hovering near eaves, decks, and porch roofs. It is essential to be cautious while having carpenter bees wandering near you cause male carpenter bees work as “patrol officers” and can be aggressive when defending their territories; the good news is that their aggression is just a show, as they cannot sting. Female carpenter bees are not aggressive and do not usually defend their nesting sites, although they can sting if handled.
Carpenter bees, while relatively harmless, increase the number of nests with time, causing considerable damage to wood. They can also leave marks with their feces.
People are typically alarmed when they see carpenter bees crawling out of wood. Females can sting, but only if provoked. Males appear hostile while flying about people and pets, however they are not dangerous because males lack a stinger.
While these pests can cause wood damage, there are several simple things homeowners can do to keep them at bay, such as painting wood and keeping outside doors locked to restrict carpenter bee access to wood that could be used to build galleries.
Lifecycle of a Carpenter Bee
Adult bees overwinter in wood tunnels and emerge to mate the following spring. After creating new space for space in the existing burrows for eggs, female bees stock the cambers with bee bread, deposit one egg, and seal each chamber.
Typically, eastern bees produce 6-8 eggs at a time. The bee spends an average of two days as an egg, 15 days as larvae, four days in the prepupal stage, and fifteen days as a pupa.
Adults emerge in August, feed, and then return to the same nest to overwinter and begin the process. Overall, carpenter bees (and bees generally) may live as long as three years.
Are Carpenter Bees Dangerous?
Carpenter bees are generally harmless, although their presence near the entrance of a house or building can be concerning. Female carpenter bees rarely sting unless they feel directly provoked and their stinger is not barbed like that of a honey bee or bumblebee.
The only real danger posed by carpenter bees is the potential damage to wood structures if they decide to make their nest inside. Their boreholes have the potential to weaken beams and posts, and their presence near buildings can lead to further damage if not taken care of.
How to Identify a Carpenter Bee
These bee species are robust and can measure up to 1 inch long. The upper surface of their abdomens is mainly bare and appears shiny black. The thorax is covered in orange, yellow, or white hair. Their head is almost as broad as their thorax. These bees have a dense quantity of hairs on their hind legs.
Resembling bumblebees, carpenter bees have the same size except for their head, with the bumblebee’s head being much narrower than the thorax. Bumblebees have very hairy abdomens with yellow markings and large pollen baskets on their hind legs. As social insects, bumblebees live in colonies with nests typically in the ground.
Where are Carpenter Bees Found?
As solitary insects, carpenter bees do not build colonies. Each female bee creates its nest gallery inside of a wood surface. Several carpenter bees often use the same piece of wood, with galleries happening close to each other, but each bee behaves independently of other members.
Male and female bees emerge in April throughout spring and mate. Territorial males hover nearby as mated females begin nesting activities.
The gallery construction is an energy and time-consuming process; female carpenters preferentially refurbish an old nest instead of creating a new one. Female carpenters bees may use an existing galley, lengthen it, or excavate a new gallery from an already-existing entrance hole.
To create a new nest, female carpenter bees use their strong mandibles to excavate a round clean-cut entrance hole slightly less than a ½ inch wide, approximately the diameter of their body.
She then bores into the wood perpendicular to the grain and turns and excavates along the wood grain for around 4 to 6 inches to create its gallery (tunnel). She excavates it at the rate of around 1 inch per six days.
Each carpenter bee creates a series of provisioned brood cells inside the gallery. The larval provision consists of pollen and regurgitated nectar ball mix. Females form a food ball at the far end of the excavated gallery, lay their eggs on top of the mass, and then the walls off the brood cell with chewed wood pulp.
Female carpenter bees often create six to ten partitioned brood cells linearly in one gallery and then die soon after that. Male carpenter bees, likewise, are short-lived. Larvae feed on the nectar/pollen food mass, which is enough for them to develop to the pupal stage and adult stage.
Do Carpenter Bees Sting?
If you see a carpenter bee darting and buzzing aggressively toward you, it is probably a male bee. Male carpenter bees do not have a stinge, so they’ll put on a threatening display as a defense mechanism.
Female carpenter bees, on the other hand, have stingers that contain venom, and unlike other flying insects, they’re able to sting more than once. Female bees tend to stay close to their eggs, so you’ll unlikely encounter them unless you disturb their nest; they will only sting if they feel directly provoked.
Damage Caused by Carpenter Bees
Carpenter bees can cause damage to wooden structures, including decks, eaves, fences, and wooden furniture. They’re considered a serious property nuisance and even treated as they can cause structural damage if not treated.
They create tunnels by boring into untreated or weathered wood, usually targeting softwoods like cedar, redwood, or pine. The entry holes they create are typically round and about half an inch in diameter.
While the damage caused by carpenter bees can be unsightly, it’s essential to note that they generally pose minimal risk to the structural integrity of wooden elements.
Unlike termites, carpenter bees do not consume wood as their primary food source. Their tunnels are mainly used for nesting purposes and do not extend deep into the wood.
Over time, weathering and exposure to the elements can cause untreated wood to develop cracks, which can make it more susceptible to carpenter bee activity. However, regular maintenance and sealing of wooden structures can help minimize the potential damage caused by carpenter bees.
Although carpenter bees’ direct damage to wood is typically limited, their activities can attract woodpeckers and other secondary pests. The large larvae developing into tunnels in homes are often attractive to woodpeckers who seek out developing carpenter bees and expand damage to existing holes.
Signs of a Carpenter Bee Infestation
Carpenter bees create distinct round entry holes in wood, typically about half an inch in diameter. These holes are smooth and may appear as perfectly drilled circles on the surface of wooden structures. Keep an eye out for these entry holes, especially in untreated or weathered wood.
As carpenter bees tunnel into wood, they push out the wood particles or frass. This results in the accumulation of sawdust-like material below the entry holes. You may notice small piles of sawdust or frass near the holes, indicating carpenter bee activity.
Another sign of carpenter bee infestation is the presence of bees near wooden structures. Male carpenter bees, which are often more noticeable due to their territorial behavior, may hover around nesting sites or fly in a distinct zigzag pattern. Female bees may be seen entering or exiting the entry holes.
Woodpeckers are natural predators of carpenter bees. If you notice increased woodpecker activity, such as pecking or drilling holes in wooden structures, it could be an indication of carpenter bee infestation. Woodpeckers are attracted to the carpenter bee larvae and seek them out as a food source.
Over time, continuous carpenter bee activity can result in visible damage to wooden structures. Look for signs of wood deterioration, such as soft or weakened areas, splintering, or crumbling wood around the entry holes.
However, it’s important to remember that carpenter bee damage is generally limited to the surface layers of the wood and doesn’t typically affect the structural integrity.
How to Get Rid of Carpenter Bees
Provide Alternative Nesting Sites
Since carpenter bees are attracted to untreated or weathered wood, you can discourage them from targeting your structures by offering alternative nesting options.
Set up bee blocks or bee hotels made from untreated hardwood logs or blocks of wood with pre-drilled holes. These will provide suitable homes for carpenter bees, diverting their attention away from your wooden structures.
Carpenter bee traps are simple and effective devices used to catch and control carpenter bees. The traps are typically made of pre-drilled wooden blocks attached to glass jars or plastic bottles. The bees are attracted to the wooden block, which mimics their natural nesting environment, and crawl into the pre-drilled holes. Once inside the trap, the bees are unable to escape and eventually perish. Carpenter bee traps are easy to make at home and there are also many commercially available options.
Fill Existing Bee Holes
If you have identified carpenter bee holes in your wooden structures, you can fill them with wood putty or caulk during the late fall or winter when the bees are not active.
Alternatively, you can plug the entrance hole with a wooden dowel piece coated with the carpenter’s glue. This will deter future bees from using old tunnels, wood decay, and moisture intrusion. Make sure to repaint or seal the repaired areas to prevent future infestations.
Paint or Seal Wooden Structures
The best time to attack carpenter bees is before their tunnels are entirely constructed.
To make your wooden structures less appealing to carpenter bees, consider painting or sealing them. Bees are less likely to target surfaces that are smooth, painted, or coated with varnish or polyurethane. Opt for eco-friendly, low-toxicity paints or sealants to maintain organic practices.
Stains and preservatives are less reliable than painting but may afford some repellence versus bare wood. It also helps keep garages and outbuildings closed during active bee activity.
Use Natural Repellents
Certain scents and oils can deter carpenter bees. Applying natural repellents like citrus oil, almond oil, or eucalyptus oil to wooden surfaces may discourage bees from nesting. However, keep in mind that these repellents are temporary and need to be reapplied periodically.
Promote Plant Diversity
Encouraging a diverse range of flowering plants in your garden attracts a variety of pollinators, including carpenter bees.
By providing abundant nectar and pollen sources, you can create a balanced ecosystem where carpenter bees are less likely to focus on a specific area. Native flowering plants are particularly beneficial since they have co-evolved with local pollinators.
Encourage Natural Predators
Attracting natural predators can help control carpenter bee populations since certain wasp species are known to prey on carpenter bees.
Providing suitable habitats like trees, shrubs, and wild areas can attract these natural predators to your garden.
Monitoring and Manual Removal
Regularly inspect your wooden structures for carpenter bee activity. If you notice holes or bees, you can physically remove them using a vacuum or a jar with a lid. Be sure to release them away from your property to prevent re-infestation.
Plant Repellent Herbs
Some aromatic herbs, like mint, rosemary, and thyme, have natural repellent properties that may deter carpenter bees. Plant these herbs near wooden structures to create a barrier and discourage nesting.
One of the most common ways to get rid of carpenter bees is with WD40 which is like an old farmer’s alternative to insecticides.
These products derived from petroleum will effectively eliminate all insects. To spray into the tunnels, use a spray with an extension tube.
As a last resort, you can use some insecticides. Aerosol, liquid, or dust insecticides can be applied directly to tunnel openings.
Leave the holes open for a couple of days after treating them to allow the flying insects to contact and distribute the insecticide throughout the tunnel.
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Melissa Pino is a biologist, master gardener, and regular contributor for Planet Natural. Melissa's work focuses on promoting environmentally-friendly practices, helping people create healthy gardens and finding ways to achieve overall health and wellness.